This will remove imports from __future__ that are no longer needed.

https://docs.python.org/3.5/library/2to3.html#2to3fixer-future

* Always run CSMHE migrations for every application in all contexts

This reverts commit 8c805999.

This reverts commit b0b8a76d.

This is a feature that has been deprecated and can be safely removed.

DEPR-7

relied on the old configuration values and old way of validating
passwords. Also improved registration page by always showing error
messages rather than hiding them on leaving the field.

This reverts commit 105db2cf, reversing
changes made to 44745759.

This reverts commit 9a70ca78, reversing
changes made to efd5b9ab.

Hopefully fixes EDUCATOR-3053

This reverts commit 18d93b00.

Reapplies edx/edx-platform#17509

This reverts commit 0f7e2373.

EDUCATOR-171